You don't need to make a purchase to enter contests such as Tim Hortons' Roll Up The Rim To Win. But sometimes the alternatives are just as costly. (Tim Hortons )

Despite the well-known slogan, you don't actually have to roll up the rim to win.

As with most retail contests, the signature Tim Hortons promotion has a standard clause in the fine print saying no purchase is necessary to play.

In the case of Tim Hortons, people have the option of mailing a letter to the company's office in Saint John, N.B., requesting a free cup. Entrants must include a self-addressed envelope with proper postage.

People can also write in for a receipt that counts as proof purchase, which can be uploaded to the company's website for a chance to win a prize.

But is it worth it, especially when you consider the cost of the two envelopes and two stamps?

Jody Luddington won a $5 gift card by mailing in for a contest receipt. She says it's the most she's ever won playing roll up the rim. (Blair Sanderson/CBC)

"So then technically you are purchasing a cup of coffee, just in a different way," said longtime Tims drinker Jody Luddington.

After some insistence, she agreed to give it a try.

Luddington sent in a request for a receipt on Feb. 22 and got a reply March 7. After uploading a picture of the receipt to the company website, she was notified she'd won a $5 gift card that would be sent in the mail.

Why the option exists

Sandra Grauschopf covers the niche beat of contests and sweepstakes for the website The Balance.com. The fine print is all about staying on the right side of the law, she said.

"The U.S. and Canada both have laws about who can run a lottery and the lottery is generally something that can be run by the government."

To avoid being classified as an illegal lottery, sweepstakes must be free to enter, said Grauschopf. If a contest has a pay method of entry, then it must also offer a free method, she said.

There's a lot of leg work involved in playing without purchase. Jody Luddington says she nearly quit when she was asked to upload a photo of her receipt. (Tim Hortons)

What about those stamps?

Greg Goodson runs a company called Rafflecopter, which sells software that helps businesses run promotional contests.

"Even though you're paying technically for the envelope and the stamp, since the company is not profiting for that, technically, it's still legal," he said. "However, it's still a pain for the end user."

While it doesn't seem worth it to bother with the alternate method of entry when it comes to Tim Hortons, Grauschopf said there are other cases when finding the free method can pay off.

'There's a whole community out there'

For instance, if an appliance store has a contest in which the purchase of a washing machine earns a chance for a prize, there should be a free method of entry as well.

"There's a whole community out there that will enter sweepstakes as a hobby," said Goodson. "If a sweepstakes has 10 ways to enter, most people will only enter one or two ways. But then you have sweepstakes fanatics who'll maximize the chances by entering in the most ways possible."

As for Tim Hortons, the company would not say how many people take advantage of its no-purchase-necessary clause.